Japanese Patent Application Publication No. 2005-156455 to [*first-inventor-name-et-al.] is representative of an optical fiber unit in this art (see optical fiber unit 10). FIG. 25 of inventor-name-et-al. is a perspective view of the described optical fiber unit. FIG. 26 is a perspective exploded view of the optical fiber unit 10.
As shown in FIG. 26, the optical fiber unit 10 described by first-inventor-name-et-al. includes head 11, cover 12, and nut 13. The head 11 includes a cylindrical portion 14 and an optical fiber holder 17. The cylindrical portion 14 includes a through-hole 18, in which an optical fiber cable 15 is inserted. The optical fiber holder 17 includes a groove 22, which communicates with the through-hole 18. The optical fiber holder 17 is shaped in a hexagonal prism defining the groove 22. The optical fiber holder 17 has an opening 23 in one side of its periphery. The optical fiber cable 15 is inserted in the through-hole 18 of the cylindrical portion 14 and in the groove 22 of the optical fiber holder 17, bent at a predetermined curvature and then extends from the opening 23.
In the optical fiber unit 10 described by first-inventor-name-et-al., optical fiber cable 15 extends from opening 23 in one side of a hexagonal prism. Optical fiber cable 15 extends in a direction that is not parallel to the sides on which a jig 30, such as a spanner, is set. In this case, the jig 30 can contact with optical fiber cable 15 and thus damage the optical fiber cable 15. To avoid contact with optical fiber cable 15, the jig 30 cannot be completely engaged with optical fiber holder 17.
FIG. 27 is a schematic view showing the jig 30 set on the optical fiber holder 17. If the jig 30 set in the state shown in FIG. 27 is further pushed in to engage with the optical fiber holder 17 at its deeper position, the jig 30 can come in contact with the optical fiber cable 15 and damage the optical fiber cable 15. If such contact with the optical fiber cable 15 is avoided in the manner shown in FIG. 27, the jig 30 would be set incompletely on the optical fiber holder 17. However, this causes the problem of, disabling secure grasping of the optical fiber holder 17 with the jig.